Method for displaying calibration-required data

ABSTRACT

Calibration-required data displayed by an industrial visual display system, which can be configured using a predetermined configuring software and which has a standard interface for integrating additional applications. To this end, the calibration-required data are integrally protected and optionally encoded. The calibration-required data are then transmitted to the visual display system and decoded therein by an application that is integrated via the standard interface, after which they are visually displayed in a form that is different from the presentation possibilities that can be configured by the configuring software.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the US National Stage of International ApplicationNo. PCT/DE2003/003859, filed Nov. 21, 2003 and claims the benefitthereof. The International Application claims the benefits of Germanapplication No. 10254629.0 filed Nov. 22, 2002, both applications areincorporated by reference herein in their entirety.

FIELD OF THE INVENTION

The invention relates to a method for displaying calibration-requireddata.

SUMMARY OF THE INVENTION

In measurement systems in production, goods distribution or other plantmeasured value recorders and measured value displays are generallydistributed across the plant, with the measured values or measurementdata being transmitted from the measured value recorders to the measuredvalue displays. The measurement data is increasingly displayed usingfreely-programmable PCs. In addition the measurement data is included asa rule for the control of the plant. By contrast with measuring devicesin which the measured value recorder and the measured value display areintegrated into one device, software, i.e. data transmission andprocessing have a prominent role to play in measurement systems. This istaken into account in the Guidelines 7.1 of the European Cooperation inLegal Metrology (WELMEC): “Software Requirements on the Basis of theMeasuring Instruments Directive” dated October, 1999(www.welmec.org/publications/7-1.pdf) in relation to the transmissionand display of calibration-required data. One of the proposals in thisdocument is that calbration-required data which is transmitted over anon-encapsulated transmission path, for example a network, should beencrypted to protect it from manipulation. To ensure the authenticity ofthe data when it is received, the address of the relevant sender can betransmitted together with the data. Additionally combining thecalibration-required data to be transmitted with a time stamp enablesthe currency of the data to be checked on receipt. In relation to thedisplay of the calibration-required data on a PC with a Windowsinterface there is a requirement for the data to be presented in awindow which is automatically always moved into the foreground andcannot be covered by other windows, for the calibration-required data tobe presented in the window in a form which cannot be confused with theother windows, and for the window which displays thecalibration-required data to be administered by a calibration-requiredpart of the program, that is a part of the program protected fromdeliberate changes by means of widely-used software tools (texteditors).

The object of the invention is to specify a predictable method fordisplaying calibration-required data which satisfies the above-mentionedWELMEC requirements.

In accordance with the invention the object is achieved by displayingthe calibration-required data by means of an industry visualizationsystem which can be planned using predetermined project planningsoftware and has a standard interface to incorporate furtherapplications, with the calibration-required data being transmitted tothe visualization system with its integrity ensured and being visualizedvia one of the applications incorporated into the standard interface ina way other than that provided by the presentation options able to beplanned via the project-planning software.

Industry visualization system here is taken to mean an operation andmonitoring device or HMI (Human Machine Interface) device as is used inparticular in process automation systems. Functions, switches or processvalues are visualized on a so-called operator or touch panel. With theaid of this visualization processes, error messages or process valuescan be displayed in an easy-to-understand way to the viewer. Recordingthe processes visually, for example in the form of process images, makesoperation easier for the user. The visualization system can be connectedvia a data connection to the process automation system and allowsproject-specific function keys, buttons or display elements to be usedto influence the project. The visualization system is planned usingprespecified project planning software which enables ideas to beconverted simply and rapidly into simple and easy-to-understand imagesfor the visualization system without the user having to have anyspecific program knowledge to perform these operations. To allow an openvisualization system to be achieved while retaining ease of projectplanning, this system has one or more standard interfaces. Examples arefor graphics import of BMP, WMF, TIF images, for data exchange DDE,ODBC, RAS and for the Integration of applications OLE and ActiveX. Theseinterfaces provide a simple method of exchanging data between individualsoftware products. ActiveX for example (previously also known as OCX-OLECustom Control) allows ready-made application components to beincorporated into another application, for example into a visualizationsystem. Process visualization can thus be enriched by functionalitiesfor which there is no provision in the project planning software. Themethod in accordance with the invention advantageously uses a standardinterface of an industry visualization system, allowing an applicationto be incorporated into the visualization system via this interface withwhich the calibration-required data with ensured integrity can bevisualized in a form complying with the WELMEC guidelines.

If the calibration-required data is transmitted within a plant whichcounts as closed, safeguarding its integrity can be sufficient to meetthe WELMEC requirements. If the transmission path, as in telephonenetworks for example, is to be regarded as open, encryption of thecalibration-required data to be transmitted is necessary. In this casethe encrypted data is decrypted in the visualization system by theapplication linked in via the standard interface.

The encryption of confidential data before transmission to a receiver isgenerally known. In what is known as the public encryption method thesender uses a public key of the authorized recipient for encryption ofthe data, so that only this recipient can decrypt the data with his ownprivate key. The sender can authenticate the data by signing it. To dothis the sender encrypts the data with his own private key while therecipient uses the sender's public key to decrypt the data. Dataencrypted with public keys is not necessarily authentic whereas datasigned with private keys is not confidential. To establish theconfidentiality and authenticity data encryption and signing can thus becombined, to which end the sender first encrypts the data with his ownprivate key and then with the recipient's public key. This is alsopossible with the method in accordance with the invention. Preferablyhowever the calibration-required data is encrypted on the sender sidewith a private key and decrypted on the receiver side with the sameprivate key. The private keys are integrated when the send device, forexample a display module, and the receive device, in this case thevisualization system, are manufactured. To finally guarantee theintegrity, i.e. the incorruptibility of the transmitted data, thetransmitter can determined the data from a check code which is sentencrypted to the recipient. The recipient decrypts the check code andcompares the check code thus decrypted with the check code computed fromthe received data; if the two check codes are the same, the integrity ofthe data is ensured. To enable data coming from different senders to bedisplayed unmistakably on one and the same visualization system, theaddress of the relevant transmitter can be sent encrypted together withthe data and subsequently visualized together with the associated data.Additionally combining the calibration-required data to be transmittedwith a time stamp finally enables the currency of the data to be checkedon receipt.

As already explained the calibration-required data is presented on theindustry visualization system in a form which cannot be planned with theproject planning software. This can occur in that thecalibration-required data is visualized in a display area of thevisualization system not accessible to the project planning software andthus reserved exclusively for display of the calibration-required data.Additionally or alternatively the calibration-required data can bevisualized together with additional information which cannot be plannedby the project planning software, for example a typical watermark in thebackground.

For further explanation of the method in accordance with the inventionreference is made below to the single FIGURE of the drawing which showspart of an automation system.

BRIEF DESCRIPTION OF THE DRAWING

The sole FIGURE shows a part of an automation system.

DETAILED DESCRIPTION OF THE INVENTION

A process scale (weighing module) 1 is arranged in the automation systemwhich communicates via a backplane bus 2 with of a CPU module 3 of theautomation system. The CPU module 3 is connected just like an industryvisualization system 4 to a field bus system 5, e.g. Profibus, of theautomation system.

In the encapsulated weighing module 1 calibration-required weighing datagenerated by a weighing cell not shown in this diagram is combined witha designation of the weighing module 1, a time stamp (date, time ofday), if necessary further parameters and a check code computed fromthis data to form a metadata record and is encrypted with a private key.This encrypted metadata record is transmitted via the backplane bus 2 tothe CPU subassembly 3 and stored there together with unencrypted data ina memory. The unencrypted data can be weighing data of the weighingmodule, provided this weighing data is not intended forcalibration-required applications, i.e. it is included for example forcontrol purposes within the automation system.

To present the calibration-required weighing data the encrypted data setis transmitted via the unencapsulated field bus system 5 to the industryvisualization system 4. This can be included in the project via aproject planning interface by means of predetermined project planningsoftware which allows specific presentations and forms of presentation.The industry visualization system 4 further features a standardinterface for incorporating further applications into the industryvisualization system 4, e.g. ActiveX-elements in this instance. SuchActiveX elements are used to decrypt the data record, with the sameprivate key being used as in the weighing module 1. The ActiveX element,by comparing the decrypted check code with the check code computed fromthe received data, checks the integrity of the data and displays theweighing data and the designation of the associated weighing module 1 ona display 6 of the industry visualization system 4. In this case thedata is presented in a form which could not be planned in the projectplanning software. This is done for example in a window 7 which cannotbe covered by other windows and of which the background displays aunique watermark 8, e.g. fine wavy lines. The decrypted data is notavailable as internal variables, so that they can also not be modifiedand can be presented in the same way.

1. A method for displaying calibration-required data by using anindustry visualization system, wherein the visualization system can beplanned via a project planning software, and wherein the visualizationsystem has a standard interface for linking further applications, themethod comprising: transmitting the calibration-required data with itsintegrity safeguarded to the visualization system; and visualizing thedata in the visualization system by an application linked via thestandard interface in a different form from the presentation optionswhich can be planned via the project planning software, wherein thecalibration-required data is visualized in a display area of thevisualization system not accessible by the project planning software. 2.The method in accordance with claim 1, wherein the calibration-requireddata is transmitted encrypted, and wherein the calibration-required datais decrypted in the visualization system via the application linked viathe standard interface.
 3. The method in accordance with claim 2,wherein the calibration-required data is encrypted with a private keyand decrypted with the same private key.
 4. The method in accordancewith claim 1, wherein the calibration-required data is visualizedtogether with additional information that cannot be planned by theproject planning software.
 5. The method in accordance with claim 1,wherein the visualization system is projected by a predetermined projectplanning software.
 6. A method for displaying calibration-required databy using an industry visualization system, wherein the visualizationsystem can be planned via a project planning software, and wherein thevisualization system has a standard interface for linking furtherapplications, the method comprising: transmitting thecalibration-required data with its integrity safeguarded to thevisualization system; and visualizing the data in the visualizationsystem by an application linked via the standard interface in adifferent form from the presentation options which can be planned viathe project planning software, wherein the calibration-required data isvisualized together with additional information that cannot be plannedby the project planning software.
 7. A method for displaying datasubject to an obligatory calibration, providing an industrialvisualization system projected by a predetermined project planningsoftware and having a standard interface for incorporating furtherapplications; transmitting the data to the visualization system bysecuring integrity of the data; and visualizing the data in thevisualization system by an application incorporated via the standardinterface in a different form from presentation options which can beprojected by the project planning software, wherein the data isvisualized in a display area of the visualization system not accessibleto the project planning software.
 8. The method in accordance with claim7, wherein the data is transmitted encrypted and decrypted in thevisualization system via the application incorporated via the standardinterface.
 9. The method in accordance with claim 8, wherein the data isencrypted with a private key and decrypted with the same private key.10. A method for displaying data subject to an obligatory calibration,providing an industrial visualization system projected by apredetermined project planning software and having a standard interfacefor incorporating further applications; transmitting the data to thevisualization system by securing integrity of the data; and visualizingthe data in the visualization system by an application incorporated viathe standard interface in a different form from presentation optionswhich can be projected by the project planning software, wherein thedata is visualized together with additional information that cannot beprojected via the project planning software.